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Configure Transit Gateway sharing

This document describes how to configure and verify communication between VPCs in two different projects using the Transit Gateway sharing feature as shown below.

Image Configure Transit Gateway sharing

Step 1. Prepare prerequisites​

This document assumes that a VPC and a Virtual Machine have already been created in two different projects.
To follow the scenario described in this document, create a VPC and a Virtual Machine in each project by referring to the service documentation and the information below.

Example VPC / Virtual Machine configuration​
CategoryProject AProject B
ProjectProject that sharesProject that receives the share
VPC IP10.0.0.0/16172.16.0.0/16
Virtual Machine IP10.0.1.167172.16.3.124

Step 2. Create and share Transit Gateway​

The following describes how to create a Transit Gateway in Project A and share it with Project B.

  1. Refer to Create Transit Gateway and create a Transit Gateway in Project A, which will share the VPC.
    • The Transit Gateway created in Project A is referred to as Tgw-1.
  2. Refer to Share Transit Gateway and share the Transit Gateway (Tgw-1) created in Project A with Project B.
  3. In Project B, verify that the Transit Gateway (Tgw-1) appears in the Transit Gateway list.

Step 3. Create attachments and configure routing​

To configure the resources connected to the Transit Gateway and the traffic routes, create attachments and configure routing in each project.

  1. Project A: Refer to Create attachment and create an attachment for Tgw-1.
    Set the resource to the VPC (10.0.0.0/16) and the subnet where the Virtual Machine is created.

  2. Project B: Refer to Create attachment and create an attachment for Tgw-1.
    Set the resource to the VPC (172.16.0.0/16) and the subnet where the Virtual Machine is created.

info

If the Share acceptance setting was configured as Automatic when creating the Transit Gateway in Project A, the attachment created in Project B is created immediately.
If it was configured as Manual, the Transit Gateway status may remain Pending Approve, and Project A must approve it.
For more information about approval, see Approve attachment.

  1. Refer to Add connection and Add route, then associate the created attachments with the route table and configure routing.

    DestinationTarget
    Attachment of Project A10.0.0.0/16
    Attachment of Project B172.16.0.0/16

Step 4. Configure VPC route tables​

To route traffic received from the Transit Gateway, configure route tables in the VPC of each project.

  1. Project A: Refer to Add route and add a routing rule for the Transit Gateway in the VPC route table.

    DestinationTarget typeTarget
    172.16.0.0/16Transit GatewayTgw-1 (Transit Gateway created in Project A)

  2. Project B: Refer to Add route and add a routing rule for the Transit Gateway in the VPC route table.

    DestinationTarget typeTarget
    10.0.0.0/16Transit GatewayTgw-1 (Transit Gateway created in Project A)

Step 5. Verify results​

  1. From the Virtual Machine in Project A (10.0.1.167), perform a ping test to the Virtual Machine in Project B (172.16.3.124) to verify that the Transit Gateway sharing works correctly.

    Verify result
    ping 172.16.3.124

  2. From the Virtual Machine in Project B (172.16.3.124), perform a ping test to the Virtual Machine in Project A (10.0.1.167) to verify that the connection works in both directions.

    Verify result
    ping 10.0.1.167